the only habitat for many important wildlife species, particularly in agricultural landscapes.
Intermittent stream residents are often specialists, having developed adaptations that allow them to fill unique niches within their ecosystem. Recent Conservation Department research found 36 kinds of invertebrates that occurred only in intermittent streams in our state. These little critters are adapted to the wet/dry cycle and cannot live in either perennial or ephemeral streams. For example, the eggs of some stoneflies sometimes remain dormant for several years until streams are rewetted. Some caddisflies have drought-resistant pupal cases.
Other organisms have also developed wet/drought life cycles. Missouri salamanders often prefer intermittent streams to perennial streams, burrowing into wetted stream bottoms when the stream dries. Many Missouri fish species find intermittent streams an ideal habitat for a portion of their life cycles; minnows, shiners, darters, sculpins and madtom catfish species migrate to stagnant, isolated pools as streams dry and feed on the abundant insect life there. The Conservation Department recently found that 111 intermittent study streams contained 85 different fish species, with an average of nine but up to 28 distinct species per stream. Common fishes included channel catfish, sunfish, black bass, goggle-eye, crappie and rainbow trout.
Some endangered and economically important species rely on intermittent streams for spawning and nursery sites, and many more species depend on these streams for critical stages in their life cycles. Missouri’s rarest crayfish species, the Mammoth Spring crayfish, occurs in only three streams in the state, two of which are intermittent. Reptiles, birds and mammals use the vegetated corridors around intermittent streams and feed on the abundant life within them.
Intermittent streams are not only tremendous meeting places for swimming, crawling and flying wildlife to gather, but their other functions are equally vital to wildlife and people. Intermittent streams recycle important nutrients and energy that sustain the biological productivity of downstream rivers and lakes, keeping fish populations healthy and strong. These streams recharge surface and groundwater supplies for our drinking, bathing, irrigation and industrial uses. This water recycling keeps our river and lake water-clarity high, ideal for sport fishing and other recreation. Intermittent streams help control floods by slowing flows and providing floodplains for floodwaters to disperse and recede faster. So, these small streams also hold critical economic value to our society.
Human activities often threaten intermittent streams, possibly because it’s easy to overlook their importance due to their small size